The present invention relates to an agricultural chemicals composition to scatter (apply) directly on the water surface of a rice paddy field, water for irrigation, a pond and the like, the preparation thereof and the method for scattering (applying) the same.
At present, as a major agricultural chemicals formulation, a granulated type, a powder type, an emulsifiable type, a wettable type, a suspension type, a granulated hydrate type and so on are known. In recent years, saving labor for scattering (applying) agricultural chemicals and cutting down of agricultural chemicals have become important and improvement of the formulation form of the agricultural chemicals is required.
Under these circumstances, recently, labor-saving formulations which can be scattered (applied) only by throwing the agricultural chemicals from a path between rice paddy fields without entering into the rice paddy have been studied. Such a formulation is premised on being scattered in a rice paddy field unevenly, and therefore it has been demanded to develop a formulation whose agrochemically active ingredients float and spread on the water surface without sedimentation of the agricultural chemicals formulation at the treatment (application) point to obtain a desirable spreadability of the components.
Various studies have been made for such a demand, but actually no agricultural chemicals formulation has been obtained, which is perfectly satisfactory for agrochemically active ingredients having various properties. For instance, a method to pack emulsion containing an agrochemical insecticide ingredient in a water-soluble film and to throw it into a submerged paddy field is disclosed (Japanese Patent Publication No. Sho 42-5240). However, the technology disclosed here has a disadvantage that a large quantity of the agricultural chemicals ingredients remain in the soil at the point of throwing after the treatment.
Various technologies are known, for instance, a formulation in which agrochemically active ingredients are impregnated into a foamed plastic material having particle sizes of 0.1 mm to 10 mm and packed with a water-soluble film (Japanese Patent Laid-open No. Sho 53-99327); an agricultural chemicals formulation for throwing into a paddy field in which water-floatable solid agricultural chemicals containing an agrochemically active ingredient, a water-floatable granular nucleus chosen from calcined vermiculite, foamed pearlite, foamed shirasu, and cork, a specific surfactant (acetylene alcohol) are packed with a water-soluble film (Japanese Patent Laid-open No. Hei 6-336403); and a formulation in which agrochemically active ingredients of agricultural chemicals are coated on and carried by a granular nucleus such as pumice or calcined pearlite having apparent specific gravity of less than 1 and particle sizes of 0.3 mm to 1.4 mm and packed with a water-soluble film (Japanese Patent Laid-open No. Hei 9-183701). However, there may arise a problem in spreadability of the components because a portion of the formulation settles down on the bottom of the water at the point of the treatment (application), and a disadvantage that since much quantity of the agrochemically active ingredient still remains on the granular nucleus made of a foamed plastic material, pumice, calcined pearlite, or the like after the treatment (application), the desired effect of the agricultural chemicals can not be exhibited but, on the contrary, phytotoxicity may arise from bringing the agricultural chemicals gathered together by the wind.
Furthermore, as for a granular water-floatable insecticide in which an insecticide is coated on atactic polypropylene granules using a binder (Japanese Patent Publication No. Sho 45-9560), and a floatable granular formulation in which an insecticide component is firmly fixed on calcined pearlite with polybutene (Japanese Patent Publication No. Sho 47-1240), since much quantity of the agrochemically active ingredients remain on the granular nucleus, as similarly as above, the result is not only that the desired effect of the agricultural chemicals can not be exhibited but phytotoxicity may arise because the agricultural chemicals are gathered together by the wind.
In addition, in the conventional art, it has been difficult to obtain a labor-saving scattering (application) type formulation containing agrochemically active ingredients which are liquid at room temperature.
In an agricultural chemicals formulation to be thrown directly into a submerged rice paddy field to be scattered, an object of the present invention is to provide a composition having an excellent spreadability without stagnation of agrochemically active ingredients at the point of treatment, and in particular, to realize a labor-saving scattering (application) type formulation containing agrochemically active ingredients which are in a liquid state at room temperature, which has been hitherto difficult to realize. Further, it is an object to make the formulation contain a high concentration of the agrochemically active ingredients in a liquid state at room temperature.
As a result of assiduous study to achieve the above-described objects, the present inventors have found that a formulation using a granular nucleus coated with a water-soluble polymer or a water-swellable substance, to hold an agrochemically active ingredient is possible to be scattered (applied) on a rice paddy field only by being thrown from a path between the paddy fields without entering into the paddy fields and, in addition, it has excellent spreadability without sedimentation of the formulation at the point of the treatment (application). Based upon this finding, the inventors have accomplished the present invention.
That is, the present invention is to provide an agricultural chemicals composition, which is prepared by letting a granular nucleus coated with a water-soluble polymer or a water-swellable substance hold an agrochemically active ingredient.
In addition, the present invention is to provide a method of producing the above-described agricultural chemicals composition comprising the step of letting an impregnation-treated granular nucleus which is obtained by impregnating the granular nucleus with solution of a water-soluble polymer or disperse liquid of a water-swellable substance and then removing the solvent thereof by evaporation, hold agrochemically active ingredients and surfactants.
Furthermore, the present invention is to provide a method of scattering (applying) the above-described agricultural chemicals composition, comprising the step of throwing it directly in a submerged paddy field at a rate of 20 g to 2,000 g of the agricultural chemicals composition or 2 to 20 bags of the agricultural chemicals composition packed with a water-soluble film per 10 are of the paddy field.